Spot the Hockey Stick #15: NOAA and a reply to Jerry Pournelle

(John A): On Jerry Pournelle’s fascinating weblog, a poster has mentioned Steve McIntyre’s expanded horizons into the world of multiproxy studies and the revealing reply to the NAS Panel by D’Arrigo in praise of cherrypicking proxies because "that’s what you have to do if you want to make cherry pie".

Jerry responds:

The basis assumption of statistical inference is random selection of the sample. If that assumpti0n is not met, other inferential tools are required.

Am I correct in concluding that the Hockey Stick has rather quietly vanished as its assumptions were exposed?

Do understand that exposing the alarmists as having systematically selected data is not the same as proving they are wrong; it does mean they have not accounted for all the data.

Later he adds:

Pity it’s not science yet. I would think it important to turn real science loose on a problem of this importance.

It’s been more than a year since the last post on the climate science version of "Where’s Wally?". The Hockey Stick has hardly vanished. A commenter noticed that NOAA persists in presenting the Hockey Stick as fact:

In the early days of paleoclimatology, the sparsely distributed paleoenvironmental records were interpreted to indicate that there was a "Medieval Warm Period" where temperatures were warmer than today. This "Medieval Warm Period" or "Medieval Optimum," was generally believed to extend from the 9th to 13th centuries, prior to the onset of the so-called "Little Ice Age."

In contrast, the evidence for a global (or at least northern hemisphere) "Little Ice Age" from the 15th to 19th centuries as a period when the Earth was generally cooler than in the mid 20th century has more or less stood the test of time as paleoclimatic records have become numerous. The idea of a global or hemispheric "Medieval Warm Period" that was warmer than today however, has turned out to be incorrect.

This is fascinating to me that "the early days of paleoclimatology" were so recent. It makes me feel old that I can remember such ancient times as if they were yesterday.

For example, Mann et al. (1999) generated a 1,000 year Northern Hemisphere temperature reconstruction (shown above) using data from multiple ice cores and tree ring records. This reconstruction suggests that the 1998 annual average temperature was more than two standard deviations warmer than any annual average temperature value since AD 1,000 (shown in yellow).

In summary, it appears that the 20th century, and in particular the late 20th century, is likely the warmest the Earth has seen in at least 1200 years.

The real legacy of the Hockey Stick in the public consciousness is the notion of a stable, pre-industrial climate existing prior to the industrial revolution. That is the Big Lie underpinning climate alarmism.

I think that proof is very important. I don’t think that we should become so skeptical that we aren’t interested and curious in what happened and try our best to find inferences. Sometimes I worry that some here, don’t want to find out. Think about it this way, if I came up with a method that was a valid proxy, would that make you happy or sad? I think with all the human forensic ingenueity, eventually we will crack this nut.

Good afternoon all. I have some newbie Qs and have been waiting for the most opportune time to ask. I am a ground water hydrologist — a practitioner, not an academic — and have never taken ONE statistics course.

1. Somewhat back to basics: if PCA is used to analyze the S&P 500 in a bull market, I can see how it would be useful in identifying which stock components contributed most to the upward trend. I have trouble, however, in understanding how PCA can be used to precisely reconstruct the actual index. To me it would seem more likely that the resulting chart would be even more bullish than the index. And if so, ditto for a temperature index.

No detail needed or requested. I’m just wondering… is this is a valid thing to attempt?

2. Cutting to the chase, the Mann HS is an artifact of his normalization to 20th the century, in round numbers about 10% of the data. If I had two time series, one ranging from 0 to 1 and the other ranging from 0 to 100, I would never dream of normalizing them to only the last 10% of the data. But if I did, I certainly would not expect to find meaningful information outside of that small range. Now, I understand that Mann’s time series were not that extreme. My question is whether or not this operation is a true statistical NO-NO, never to be done. (It does not seem to raise a flag to his fellow scientists on RC.)

It seems to me Mann did this as some sort of weird attempt at calibration, which really should have been a completely separate issue.

BTW, from the gig-go the HS never passed the smell test with me. It was not that the MWP or LIA were missing. It was because there were no cyclical components at all. That went against everything I thought I knew about natural processes. But it was not until Steve and Ross came along that I had a clue about what was wrong.

I thought the ice core proxies in South America, New Zealand, and Mt Kilimanjaro along with North American, European proxies confirmed with certainty that the LIA was global, and with lesser certainty that the MWP was global. Only the Antartic is problematic.

From his testimony in front of the Senate, September 28, 2005,
he says:

“Why did the UN accept Mann’s report so uncritically? Why didn’t they catch the errors? Because the IPCC doesn’t do independent verification. And perhaps because Mann himself was in charge of the section of the report that included his work.”

“Second, the flaws in Mann’s work were not caught by climate scientists, but rather by outsiders-in this case, an economist and a mathematician. They had to go to great lengths to obtain data from Mann’s team, which obstructed them at every turn. When the Canadians sought help from the NSF, they were told that Mann was under no obligation to provide his data to other researchers for independent verification.
Third, this kind of stonewalling is not unique. The Canadians are now attempting to replicate other climate studies and are getting the same runaround from other researchers. One prominent scientist told them: “Why should I make the data available to you, when your aim is to try and find something wrong with it.”

#19 Dave, thanks. :)
Husband and I went to a dinner party this weekend. Two of the attendees had just come from seeing Gore’s movie; one was a middle school teacher. What a kafuffle of people and facts to keep straight when you are asked your opinion or asked to explain the whole picture. Sheesh.

Thank You Steve for your Integrity and Hard Work, and please keep it up!!!

A famous Scientist once said that good science provides us with more questions than answers about our universe.

Honest scientists welcome critical review and analysis of their work. “FACTS” drive the course of honest scientific research toward a conclusion. NOAA and IPCC seem to have selected conclusions and are looking for facts to support their conclusions.

Policies of the current crop of too many “Political Scientists” running climate research for NOAA the IPCC and many universitiy programs resemble the “Flat Earth” thinking in Europe about 400 to 1000 years ago when Galileo and Copernicus were persecuted for challenging the “Conventional Wisdom” which said that the universe revolved around the Earth. These and other brave and wise Scientists were persecuted for expressing their beliefs and thus challenging the Politically Correct Official Dogma-of-the-day.

You and others are the honest voices in the current discussions about whether or not humans have significant influence on climate change on this Earth.

#24. The argument for GHG caused AGW is often made that there can be no other explanation for observed warming. But logically they must have evaluated and excluded all alternatives to support this argument. Here they state:

changes in the Sun’s output of ultraviolet light, and of magnetized plasmas, cannot be ruled out.

I suggest those who believe the Medieval Warm period ‘probably did not exist’, should read, if they can decipher it, Chaucers Canterbury Tales, where the their pilgrims, during their travels encountered the effects on people, cattle and crops, of the excessive heat which caused crops to fail and water supplies to dry up; or is this a tale made up by deniers.